I'd like to help postmanbat, but am a little confused as to your meaning. Would you clarify your Q please?
To my knowledge the ears and ear coverts of the Song Thrush are no different than that of any other bird. To make certain I've just been through numerous ID books and can find absolutely no mention of anything strange or odd.
Afaik a song thrush's ears are the same as most bird's ears. The brain however is different from other birds in that they are the only ones that recognise other song thrush's song. But this is true of almost all birds. It is important that they recognise their own species for various reasons.
Birds are different to other classes of animals however in that there is only one organ that actually receives the sound waves, centrally connected to both ear canals. The slight asymetrical placing of the ears in relation to the center of the head enables the bird to determine which way the sound is coming from by calculating the time difference between the sound received by each ear canal.